Universities have been ordered to "focus more sharply on the outcomes of outreach" and set quantifiable targets on admitting students from under-represented groups.
In a long-awaited letter to the Office for Fair Access last week, Vince Cable, the business secretary, and David Willetts, the universities minister, criticise selective universities for making "inadequate" progress on admitting more students from poor backgrounds and call for "much more determined action".
However, some experts have warned that the document appears more interested in limiting the cost to government of the new fee regime than in widening participation.
The final letter of guidance, which follows a draft version in December, is notably more tough-talking and has a stronger emphasis on targets.
Offa has been asked to draw up five-year progress plans with each university, to be monitored each year via the access agreements that will be required from all institutions that charge more than £6,000.
Universities must demonstrate how their work will "impact positively" on official access and retention benchmarks, alongside their own targets, with those charging higher fees expected to set bigger goals.
The letter also gives explicit backing to the use of "contextual data".
If selective institutions are to make progress on admitting more students from disadvantaged backgrounds, it says, "they may want to admit some such students on the basis of lower entry qualifications than they would normally apply".
Ministers do not set a minimum level of expenditure on outreach, but they will consider whether there is a need for this in the autumn.
The letter also encourages universities to use fee waivers to reduce the cost of borrowing, rather than the more expensive option of "poorly targeted bursary schemes".
The sanctions available to Offa will remain the same as at present: the power to impose a fine of up to £500,000 and to refuse to renew an access agreement, thus withdrawing the university's right to charge fees above £6,000.
But Claire Callender, professor of higher education at Birkbeck, University of London and joint chair of higher education studies at the Institute of Education, said the document showed the government had "no serious mechanism" for controlling fee levels.
She said the letter also raises questions about the prime function of Offa. "Is it to safeguard access or is it to be a regulator of public expenditure?"
Andy Westwood, chief executive of GuildHE, warned that "conflating access agreements and price control mechanisms" could create perverse incentives and impede worthy policy intentions.
Access experts observed a shift in language in the letter, with more attention given to fair access (admitting more poor students into "elite" universities) than to widening participation (admitting more disadvantaged students into the system as a whole).
Professor Callender warned that the issue of widening participation should not be forgotten, particularly given the impending fees hike.
Speaking at a conference in London this week, Martin Williams, director of higher education strategy at the Department for Business, Innovation and Skills, said that there would be a greater focus on the results of work to boost access than on the amount of money spent.
There would also be more emphasis on work to prevent students dropping out, he said.